I piss all day too, not to often do I get up during the night though. I drink well over a gallon of water a day.
I'm not sure what your diet looks like, but like most here I'm sure it's a high protein one. Here's a article I found about high protein diets and frequent urinating.
Overview
The average adult produces about 1.5 liters of urine per day and eats about
79 grams of
protein. Individuals who consume three times as much protein can produce three to four liters of urine daily.
I eat over 300grams a day! That number is pretty weak)
Protein Byproducts
When protein is digested, it breaks down into water, carbon dioxide and nitrates like urea---the stuff secreted in urine. The more protein you eat, the more urea you must secrete.
Protein Synthesis
To build muscle, your body breaks protein into amino acids ("the building blocks of proteins"), then reassembles them into the proteins it needs. The process of making proteins requires water.
Lifestyle Factors
Many high-protein foods also contain a lot of
sodium, which stimulates thirst and subsequently urine production. People on high-protein diets (usually dieters and bodybuilders) also tend to be active, requiring a higher fluid intake---and output.
Caffeine
Some protein shakes and
supplements contain caffeine, which is a diuretic, meaning it makes you pee more.
Kidneys
The Brenner Hypothesis suggests that filtering extra urine is hard on the kidneys. Lonnie Lowery, Ph.D., calls this speculation. "Asking a tissue to do extra work does not equal 'damage,'" he told Testosterone Muscle. "Think about your biceps. When you ask them to do extra work... they get better!"